Pedestrian positioning via vehicle collaboration

ABSTRACT

Disclosed are techniques for using ranging signals to determine a position of a pedestrian user equipment (P-UE). In an aspect, a UE receives a plurality of ranging signals transmitted by one or more UEs, measures one or more properties of each of the plurality of ranging signals, and calculates an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals. In an aspect, the P-UE transmits a plurality of ranging signals, receives a first message and a second message from first and second vehicle UEs (V-UEs), the first and second messages including first and second estimated positions of the P-UE and associated first and second confidences, and calculates an estimate of the position of the P-UE based on the first estimated position, the first confidence, the second estimated position, the second confidence, or a combination thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application for patent claims the benefit of U.S.Provisional Application No. 62/636,762, entitled “PEDESTRIAN POSITIONINGVIA VEHICLE COLLABORATION,” filed Feb. 28, 2018, assigned to theassignee hereof, and expressly incorporated herein by reference in itsentirety.

INTRODUCTION

Aspects of this disclosure relate generally to pedestrian positioningvia vehicle collaboration.

Around the world, Vehicle-to-Everything (V2X) communication technologiesare being implemented to support Intelligent Transportation Systems(ITS) applications, such as wireless communications between vehicles(Vehicle-to-Vehicle (V2V)), between vehicles and the roadsideinfrastructure (Vehicle-to-Infrastructure (V2I)), and between vehiclesand pedestrians (Vehicle-to-Pedestrian (V2P)). The goal is for vehiclesto be able to sense the environment around them and communicate thatinformation to other vehicles, infrastructure, and personal mobiledevices. Such vehicle communication will enable safety, mobility, andenvironmental advancements that current technologies are unable toprovide. Once fully implemented, the technology is expected to reduceunimpaired vehicle crashes by 80%.

The V2P approach encompasses a broad set of road users, including peoplewalking, children being pushed in strollers, people using wheelchairs orother mobility devices, passengers embarking and disembarking buses andtrains, people riding bicycles, and the like. Pedestrian detectionsystems can be implemented in vehicles, in the infrastructure, or withthe pedestrians themselves to provide warnings to drivers, pedestrians,or both. For example, when a pedestrian who is blind or has low-visionis at a crosswalk, the pedestrian's smartphone can make a “call” to thetraffic signal associated with the crosswalk. The traffic signal canthen broadcast a message to nearby vehicles attempting to make a turn toalert them to the presence of the pedestrian at the crosswalk. Asanother example, transit bus operators can be warned when pedestrians,within the crosswalk of a signalized intersection, are in the intendedpath of the bus.

SUMMARY

The following presents a simplified summary relating to one or moreaspects disclosed herein. As such, the following summary should not beconsidered an extensive overview relating to all contemplated aspects,nor should the following summary be regarded to identify key or criticalelements relating to all contemplated aspects or to delineate the scopeassociated with any particular aspect. Accordingly, the followingsummary has the sole purpose to present certain concepts relating to oneor more aspects relating to the mechanisms disclosed herein in asimplified form to precede the detailed description presented below.

In an aspect, a method for using ranging signals to determine a positionof a pedestrian user equipment (P-UE) includes receiving a plurality ofranging signals transmitted by one or more UEs, measuring one or moreproperties of each of the plurality of ranging signals, and calculatingan estimate of the position of the P-UE based on the one or moreproperties of each of the plurality of ranging signals.

In an aspect, a method for determining a position of a P-UE includestransmitting, by the P-UE, a plurality of ranging signals in a pluralityof ranging resource sets, receiving, at the P-UE, a first message from afirst vehicle user equipment (V-UE), the first message including a firstestimated position of the P-UE and a first indicator of confidence ofthe first estimated position, receiving, at the P-UE, a second messagefrom a second V-UE, the second message including a second estimatedposition of the P-UE and a second indicator of confidence of the secondestimated position, and calculating, by the P-UE, an estimate of theposition of the P-UE based on the first estimated position, the firstindicator, the second estimated position, the second indicator, or acombination thereof.

In an aspect, an apparatus for using ranging signals to determine aposition of a P-UE includes a transceiver of a first UE configured to:receive a plurality of ranging signals transmitted by one or more UEs,and measure one or more properties of each of the plurality of rangingsignals, and at least one processor of the first UE configured tocalculate an estimate of the position of the P-UE based on the one ormore properties of each of the plurality of ranging signals.

In an aspect, an apparatus for determining a position of a P-UE includesa transceiver of the P-UE configured to: transmit a plurality of rangingsignals in a plurality of ranging resource sets, receive a first messagefrom a first V-UE, the first message including a first estimatedposition of the P-UE and a first indicator of confidence of the firstestimated position, and receive a second message from a second V-UE, thesecond message including a second estimated position of the P-UE and asecond indicator of confidence of the second estimated position, and atleast one processor of the P-UE configured to calculate an estimate ofthe position of the P-UE based on the first estimated position, thefirst indicator, the second estimated position, the second indicator, ora combination thereof.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions for using ranging signals to determinea position of a P-UE includes at least one instruction instructing afirst UE to receive a plurality of ranging signals transmitted by one ormore UEs, at least one instruction instructing the first UE to measureone or more properties of each of the plurality of ranging signals, andat least one instruction instructing the first UE to calculate anestimate of the position of the P-UE based on the one or more propertiesof each of the plurality of ranging signals.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions for determining a position of a P-UEincludes at least one instruction instructing the P-UE to transmit aplurality of ranging signals in a plurality of ranging resource sets, atleast one instruction instructing the P-UE to receive a first messagefrom a first V-UE, the first message including a first estimatedposition of the P-UE and a first indicator of confidence of the firstestimated position, at least one instruction instructing the P-UE toreceive a second message from a second V-UE, the second messageincluding a second estimated position of the P-UE and a second indicatorof confidence of the second estimated position, and at least oneinstruction instructing the P-UE to calculate an estimate of theposition of the P-UE based on the first estimated position, the firstindicator, the second estimated position, the second indicator, or acombination thereof.

In an aspect, an apparatus for using ranging signals to determine aposition of a P-UE includes a means for communication of a first UEconfigured to: receive a plurality of ranging signals transmitted by oneor more UEs, and measure one or more properties of each of the pluralityof ranging signals, and means for processing of the first UE configuredto calculate an estimate of the position of the P-UE based on the one ormore properties of each of the plurality of ranging signals.

In an aspect, an apparatus for determining a position of a P-UE includesa means for communicating of the P-UE configured to: transmit aplurality of ranging signals in a plurality of ranging resource sets,receive a first message from a first V-UE, the first message including afirst estimated position of the P-UE and a first indicator of confidenceof the first estimated position, and receive a second message from asecond V-UE, the second message including a second estimated position ofthe P-UE and a second indicator of confidence of the second estimatedposition, and a means for processing of the P-UE configured to calculatean estimate of the position of the P-UE based on the first estimatedposition, the first indicator, the second estimated position, the secondindicator, or a combination thereof.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description ofvarious aspects of the disclosure and are provided solely forillustration of the aspects and not limitation thereof.

FIG. 1 illustrates an example wireless communication system including avehicle in communication with one or more other vehicles and one or moreroadside access points according to at least one aspect of thedisclosure.

FIG. 2 is a block diagram illustrating various components of anexemplary vehicle according to at least one aspect of the disclosure.

FIG. 3 is a block diagram illustrating various components of anexemplary user device according to at least one aspect of thedisclosure.

FIG. 4 illustrates a method of the first mode for using ranging signalsto determine an accurate position of a pedestrian.

FIGS. 5A and 5B illustrate examples of ranging signal transmissionaccording to aspects of the disclosure.

FIG. 6 illustrates a method of the second mode for using ranging signalsto determine an accurate position of a pedestrian.

FIG. 7 illustrates a method of the third mode for using ranging signalsto determine an accurate position of a pedestrian.

FIG. 8 illustrates an exemplary method for using ranging signals todetermine a position of a pedestrian-UE according to at least one aspectof the disclosure.

FIG. 9 illustrates an exemplary method for determining a position of aP-UE according to at least one aspect of the disclosure.

FIGS. 10-11 illustrate example apparatuses represented as a series ofinterrelated functional modules according to at least one aspect of thedisclosure.

DETAILED DESCRIPTION

Aspects of the disclosure are provided in the following description andrelated drawings directed to various examples provided for illustrationpurposes. Alternate aspects may be devised without departing from thescope of the disclosure. Additionally, well-known aspects of thedisclosure may not be described in detail or may be omitted so as not toobscure more relevant details.

Those of skill in the art will appreciate that the information andsignals described below may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the description below may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof, depending inpart on the particular application, in part on the desired design, inpart on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions tobe performed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits (e.g., Application Specific Integrated Circuits(ASICs)), by program instructions being executed by one or moreprocessors, or by a combination of both. In addition, for each of theaspects described herein, the corresponding form of any such aspect maybe implemented as, for example, “logic configured to” perform thedescribed action.

As used herein, the terms User Equipment (UE), Vehicle User Equipment(V-UE) and Pedestrian User Equipment (P-UE) are not intended to bespecific or otherwise limited to any particular type of device or RadioAccess Technology (RAT), unless otherwise noted. In general, a P-UE maybe any portable (e.g., handheld) wireless communication device (e.g., amobile cellular phone, such as a “smartphone,” a tablet computer, aPersonal Digital Assistance (PDA), a wearable device, such as a “smartwatch,” a personal navigation device, etc.) used by a user tocommunicate over a wireless communications network, and may bealternatively referred to in different RAT environments as an AccessTerminal (AT), a Mobile Station (MS), a Subscriber Station (STA), aclient device, a user device, a mobile device, etc. A V-UE may be anyin-vehicle wireless communication device, such as a navigation system, awarning system, a Heads-Up Display (HUD), etc. Alternatively, a V-UE maybe a portable wireless communication device, like a P-UE, except that itbelongs to the driver of the vehicle or a passenger in the vehicle. Theterm “V-UE” may refer to the in-vehicle wireless communication device orthe vehicle itself, depending on the context.

FIG. 1 illustrates an example wireless communication system including aV-UE 110 in communication with one or more other V-UEs 120, one or moreroadside access points 140, and one or more P-UEs 160. In the example ofFIG. 1, the V-UE 110 may transmit and receive messages with the one ormore V-UEs 120 and the one or more roadside access points 140 via afirst wireless link 130. The wireless link 130 may operate over acommunication medium of interest, shown by way of example in FIG. 1 asthe medium 132, which may be shared with other communications betweenother vehicles and/or infrastructure access points, as well as otherRATs. The V-UE 110 may also transmit and receive messages with the oneor more P-UEs 160 belonging to one or more pedestrians 162 via a secondwireless link 150. The wireless link 150 may operate over acommunication medium of interest, shown by way of example in FIG. 1 asthe medium 152, which may be shared with other communications betweenother vehicles and/or infrastructure access points, as well as otherRATs. A “medium,” such as mediums 132 and 152, may be composed of one ormore frequency, time, and/or space communication resources (e.g.,encompassing one or more channels across one or more carriers)associated with communication between one or more transmitter/receiverpairs.

In an aspect, the wireless links 130 and 150 may be CellularVehicle-to-Everything (C-V2X) links. A first generation of C-V2X hasbeen standardized in Long-Term Evolution (LTE), and the next generationis expected to be defined in Fifth Generation (5G) (also referred to as“New Radio” (NR) or “5G NR”). C-V2X is a cellular technology that alsoenables device-to-device communications. In the U.S. and Europe, C-V2Xis expected to operate in the licensed ITS band in sub-6 GHz. Otherbands may be allocated in other countries. Thus, referring to FIG. 1, asa particular example, the mediums 132 and 152 may correspond to at leasta portion of the licensed ITS frequency band of sub-6 GHz. However, thepresent disclosure is not limited to this frequency band or cellulartechnology.

In an aspect, the wireless links 130 and 150 may be DedicatedShort-Range Communications (DSRC) links. DSRC is a one-way or two-wayshort-range to medium-range wireless communication protocol that usesthe Wireless Access for Vehicular Environments (WAVE) protocol, alsoknown as IEEE 802.11p, for V2V, V2I, and V2P communications. IEEE802.11p is an approved amendment to the IEEE 802.11 standard andoperates in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz) in theU.S. In Europe, IEEE 802.11p operates in the ITS GSA band (5.875-5.905MHz). Other bands may be allocated in other countries. The V2Vcommunications briefly described above occur on the Safety Channel,which in the U.S. is typically a 10 MHz channel that is dedicated to thepurpose of safety. The remainder of the DSRC band (the total bandwidthis 75 MHz) is intended for other services of interest to drivers, suchas road rules, tolling, parking automation, etc. Thus, referring to FIG.1, as a particular example, the mediums 132 and 152 may correspond to atleast a portion of the licensed ITS frequency band of 5.9 GHz.

Alternatively, the medium 152 may correspond to at least a portion of anunlicensed frequency band shared among various RATs. Although differentlicensed frequency bands have been reserved for certain communicationsystems (e.g., by a government entity such as the Federal CommunicationsCommission (FCC) in the United States), these systems, in particularthose employing small cell access points, have recently extendedoperation into unlicensed frequency bands such as the UnlicensedNational Information Infrastructure (U-NII) band used by Wireless LocalArea Network (WLAN) technologies, most notably IEEE 802.11x WLANtechnologies generally referred to as “Wi-Fi.” Example systems of thistype include different variants of Code Division Multiple Access (CDMA)systems, Time Division Multiple Access (TDMA) systems, FrequencyDivision Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA)systems, Single-Carrier FDMA (SC-FDMA) systems, and so on.

Communications between the V-UEs 110 and 120 are referred to as V2Vcommunications, communications between the V-UE 110 and the one or moreroadside access points 140 are referred to as V2I communications, andcommunications between the V-UE 110 and the one or more P-UEs 160 arereferred to as V2P communications. The V2V communications between V-UEs110 and 120 may include, for example, information about the position,speed, acceleration, heading, and other vehicle data of the V-UEs 110and 120. The V2I information received at the V-UE 110 from the one ormore roadside access points 140 may include, for example, road rules,parking automation information, etc. The V2P communications between theV-UE 110 and the P-UEs 160 may include information about, for example,the position, speed, acceleration, and heading of the V-UE 110 and theposition, speed (e.g., where the P-UE 160 is a bicycle), and heading ofthe P-UE 160.

FIG. 2 is a block diagram illustrating various components of anexemplary V-UE 200, which may correspond to V-UE 110 and/or V-UE 120 inFIG. 1. For the sake of simplicity, the various features and functionsillustrated in the block diagram of FIG. 2 are connected together usinga common bus that is meant to represent that these various features andfunctions are operatively coupled together. Those skilled in the artwill recognize that other connections, mechanisms, features, functions,or the like, may be provided and adapted as necessary to operativelycouple and configure an actual V-UE. Further, it is also recognized thatone or more of the features or functions illustrated in the example ofFIG. 2 may be further subdivided, or two or more of the features orfunctions illustrated in FIG. 2 may be combined.

The V-UE 200 may include at least one transceiver 204 connected to oneor more antennas 202 for communicating with other network nodes, e.g.,other vehicles (e.g., the one or more other V-UEs 120), infrastructureaccess points (e.g., the one or more roadside access points 140), P-UEs(e.g., the one or more P-UEs 160), etc., via at least one designatedradio access technology (RAT), e.g., C-V2X or IEEE 802.11p, over themedium 132/152. The transceiver 204 may be variously configured fortransmitting and encoding signals (e.g., messages, indications,information, and so on), and, conversely, for receiving and decodingsignals (e.g., messages, indications, information, pilots, and so on) inaccordance with the designated RAT. As used herein, a “transceiver” mayinclude a transmitter circuit, a receiver circuit, or a combinationthereof, but need not provide both transmit and receive functionalitiesin all designs. For example, a low functionality receiver circuit may beemployed in some designs to reduce costs when providing fullcommunication is not necessary (e.g., a receiver chip or similarcircuitry simply providing low-level sniffing).

The V-UE 200 may also include a satellite positioning service (SPS)receiver 206. The SPS receiver 206 may be connected to the one or moreantennas 202 for receiving satellite signals. The SPS receiver 206 maycomprise any suitable hardware and/or software for receiving andprocessing SPS signals. The SPS receiver 206 requests information andoperations as appropriate from the other systems, and performs thecalculations necessary to determine the V-UE's 200 position usingmeasurements obtained by any suitable SPS algorithm.

One or more sensors 208 may be coupled to a processor 210 to provideinformation related to the state and/or environment of the V-UE 200,such as speed, heading (e.g., compass heading), headlight status, gasmileage, etc. By way of example, the one or more sensors 208 may includean accelerometer (e.g., a microelectromechanical systems (MEMS) device),a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g.,a barometric pressure altimeter), etc.

The processor 210 may include one or more microprocessors,microcontrollers, ASICs, and/or digital signal processors that provideprocessing functions, as well as other calculation and controlfunctionality. The processor 210 may include any form of logic suitablefor performing, or causing the components of the V-UE 200 to perform, atleast the techniques provided herein.

The processor 210 may also be coupled to a memory 214 for storing dataand software instructions for executing programmed functionality withinthe V-UE 200. The memory 214 may be on-board the processor 210 (e.g.,within the same integrated circuit (IC) package), and/or the memory 214may be external to the processor 210 and functionally coupled over adata bus.

The V-UE 200 may include a user interface 250 that provides any suitableinterface systems, such as a microphone/speaker 252, keypad 254, anddisplay 256 that allow user interaction with the V-UE 200. Themicrophone/speaker 252 provides for voice communication services withthe V-UE 200. The keypad 254 comprises any suitable buttons for userinput to the V-UE 200. The display 256 comprises any suitable display,such as, for example, a backlit LCD display, and may further include atouch screen display for additional user input modes.

FIG. 3 is a block diagram illustrating various components of anexemplary P-UE 300, which may correspond to P-UE 160 in FIG. 1. For thesake of simplicity, the various features and functions illustrated inthe block diagram of FIG. 3 are connected together using a common buswhich is meant to represent that these various features and functionsare operatively coupled together. Those skilled in the art willrecognize that other connections, mechanisms, features, functions, orthe like, may be provided and adapted as necessary to operatively coupleand configure an actual P-UE. Further, it is also recognized that one ormore of the features or functions illustrated in the example of FIG. 3may be further subdivided, or two or more of the features or functionsillustrated in FIG. 3 may be combined.

The P-UE 300 may include one or more wide area network (WAN)transceiver(s) 304 that may be connected to one or more antennas 302.The one or more WAN transceivers 304 may comprise suitable devices,hardware, and/or software for communicating with and/or detectingsignals to/from WAN access points (e.g., cellular base stations), and/ordirectly with other wireless devices within a network. In one aspect,the WAN transceiver(s) 304 may comprise an LTE communication system(including C-V2X) suitable for communicating with an LTE network ofwireless base stations and/or other UEs (e.g., in the case of C-V2X);however in other aspects, the wireless communication system may compriseanother type of cellular telephony network, such as, for example, 5G.Additionally, any other type of wide area wireless networkingtechnologies may be used, such as WiMAX (IEEE 802.16).

The P-UE 300 may also include one or more wireless local area network(WLAN) transceivers 306 that may also be connected to the one or moreantennas 302. The one or more WLAN transceivers 306 may comprisesuitable devices, hardware, and/or software for communicating withand/or detecting signals to/from WLAN access points (e.g., access pointsof Wi-Fi networks (IEEE 802.11x), cellular piconets and/or femtocells,Bluetooth networks, etc.), and/or directly with other wireless deviceswithin a network. In one aspect, the WLAN transceiver(s) 306 maycomprise a Wi-Fi (IEEE 802.11x) communication system suitable forcommunicating with one or more wireless access points; however, in otheraspects, the WLAN transceiver(s) 306 may comprise another type of localarea network or personal area network, such as IEEE 802.11p, Bluetooth,etc. Additionally, any other type of wireless networking technologiesmay be used, for example, Ultra-Wide Band, ZigBee, wireless UniversalSerial Bus (USB), etc.

The P-UE 300 may also include an SPS receiver 308. The SPS receiver 308may also be connected to the one or more antennas 302 for receivingsatellite signals. The SPS receiver 308 may comprise any suitablehardware and/or software for receiving and processing SPS signals. TheSPS receiver 308 requests information and operations as appropriate fromthe other systems, and performs the calculations necessary to determinethe P-UE 300 position using measurements obtained by any suitable SPSalgorithm.

One or more sensors 312 may be coupled to a processor 310 to provideinformation related to the state and/or environment of the P-UE 300,such as motion, speed, heading, etc. By way of example, the one or moresensors 312 may include an accelerometer (e.g., a microelectromechanicalsystems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., acompass), an altimeter (e.g., a barometric pressure altimeter), etc.

The processor 310 may include one or more microprocessors,microcontrollers, ASICs, and/or digital signal processors that provideprocessing functions, as well as other calculation and controlfunctionality. The processor 310 may include any form of logic suitablefor performing, or causing the components of the P-UE 300 to perform, atleast the techniques provided herein.

The processor 310 may also be coupled to a memory 314 for storing dataand software instructions for executing programmed functionality withinthe P-UE 300. The memory 314 may be on-board the processor 310 (e.g.,within the same IC package), and/or the memory 314 may be external tothe processor 310 and functionally coupled over a data bus.

The P-UE 300 may include a user interface 350 that provides any suitableinterface systems, such as a microphone/speaker 352, keypad 354, anddisplay 356 that allow user interaction with the P-UE 300. Themicrophone/speaker 352 provides for voice communication services withthe P-UE 300. The keypad 354 comprises any suitable buttons for userinput to the P-UE 300. The display 356 comprises any suitable display,such as, for example, a backlit LCD display, and may further include atouch screen display for additional user input modes.

In the Safety Channel described above, each vehicle, such as V-UE 200,periodically broadcasts the Basic Safety Message (BSM), known also insimilar systems (e.g., Europe) as the Cooperative Awareness Message(CAM), to provide information about the vehicle. Pedestrian devices,such as P-UE 300, may also broadcast BSMs. Other systems may also existfor providing vehicular safety messages that may or may not implementthe techniques described herein (e.g., Chinese and Japanese vehiclemessaging systems).

BSMs are described in the “Surface Vehicle Standard,” SAE J2735,published by Society of Automotive Engineers (SAE) International in2015, which is incorporated herein in its entirety. Each BSM includesthe BSM Part I message and the BSM Part II DF_VehicleSafetyExtensiondata frames, DF_PathHistory, and DF_PathPrediction. Each BSM includesthe BSM Part II DF_VehicleSafetyExtension data element and DE_EventFlagsonly as long as an event is active. This data element is not included ina BSM unless at least one event flag is active, i.e., set to logical“1.” Each BSM may optionally include the BSM Part IIDF_VehicleSafetyExtension data frame and DF_RTCMPackage. Table 1illustrates the data elements (DE) and/or data fields (DF) that can betransmitted in a BSM.

TABLE 1 BSM Data Elements/Fields Req. Number Data Element/Field BSM PartI DE_DSRCMsgID DE_MsgCount DE_TemporaryID DE_Dsecond DE_LatitudeDE_Longitude DE_Elevation DF_PositionalAccuracy DF_TransmissionAndSpeedDE_Speed DE_TransmissionState DE_Heading DE_SteeringWheelAngleDF_AccelerationSet4Way DE_Acceleration (Longitudinal) DE_Acceleration(Lateral) DE_VerticalAcceleration DE_YawRate DF_BrakeSystemStatusDF_VehicleSize DE_VehicleWidth DE_VehicleLength BSM Part IIDE_EventFlags DF_PathHistory DF_PathPrediction DF_RTCMPackage

Aside from “routine” information about vehicle position and other datacarried in the BSM Part I message, the BSM can transmit informationabout safety related “events” in the BSM Part IIDF_VehicleSafetyExtension data frames, for example, hard brakingactions, that can be used to inform the driver of the receiving vehicleabout the event and/or to allow the receiving vehicle to performautomated operations in response to the event, such as automaticbraking, steering, and/or throttling for collision avoidance. When theDE_EventFlag is not active, the nominal rate at which BSMs are broadcastis 10 Hz (i.e., 10 times per second). After an initial BSM reporting asafety event, i.e., having the DE_EventFlag set to “1,” subsequent BSMs,which may still have the DE_EventFlag set to “1” (as a safety event maylast for several seconds), continue to be transmitted at a nominal rateof 10 Hz.

As described above, in V2P communications, both P-UEs and V-UEs canperiodically broadcast BSMs containing their positions and/or speeds toother vehicles and/or pedestrians to avoid collisions. The reportedposition of a pedestrian, however, may not be accurate. For example,where the position of a pedestrian is an SPS position (e.g., a GPSposition), a pedestrian who just walked out of a building may not havean accurate SPS position because SPS signals are generally weak ornonexistent in indoor environments and the P-UE will not yet haveacquired an accurate position outdoors. Even for pedestrians who havebeen outdoors for some time (e.g., walking along the street), SPSsignals may still be blocked and/or deflected by high buildings. Aswould be appreciated, broadcasting inaccurate SPS positions in BSMs isnot helpful for safety applications, and may even be dangerous.

The present disclosure introduces a pedestrian positioning protocol thatuses ranging signals to determine an accurate position of a pedestrian.The protocol has three modes. In the first two modes, the P-UE transmitsranging signals to nearby V-UEs, and in the third mode, V-UEs transmitranging signals to nearby P-UEs.

FIG. 4 illustrates an exemplary method 400 of the first mode for usingranging signals to determine an accurate position of a pedestrian (i.e.,a P-UE). At operation 402, a P-UE 300 transmits multiple ranging signalsin multiple “ranging resource pools.” A ranging resource pool mayconsist of a set of time and/or frequency resources (e.g., 10 subframesin LTE/5G terminology) and may occur periodically (e.g., once everysecond). The P-UE 300 may transmit a ranging signal in each of severalconsecutive ranging resource pools.

In an aspect, the P-UE 300 may transmit an identifier (ID) along withthe ranging signals. For example, the ID of the P-UE 300 may be encodedin the ranging signals. In an aspect, the ranging signals may beZadoff-Chu sequences, and the sequence ID of a ranging signal maycorrespond to the ID of the P-UE 300. A Zadoff-Chu sequence is amathematical sequence that, when applied to radio signals, creates asignal of constant amplitude, whereby cyclically shifted versions of thesequence imposed on a signal result in zero correlation with one anotherat the receiver. Zadoff-Chu sequences are currently used in LTE for thePrimary Synchronization Signal (PSS), Random Access Preamble (PRACH),Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel(PUSCH), and Sounding Reference Signal (SRS). By assigning orthogonalZadoff-Chu sequences to each P-UE 300, the cross-correlation ofsimultaneous transmissions from P-UEs 300 is reduced, thereby reducinginterference and uniquely identifying P-UE 300 transmissions.

In an aspect, the P-UE 300 may transmit the ranging signals describedherein only when it intends to refine its position. For example, theP-UE 300 may transmit ranging signals when the accuracy of its SPSposition is below a threshold, which, as noted above, may occur when,for example, the P-UE 300 has just come outside or when it is surroundedby tall buildings.

At 404, one or more V-UEs 200 within communication range of the P-UE 300can measure various properties of each received ranging signaltransmitted by the P-UE 300. These properties may include thetime-of-arrival (ToA) of the ranging signal with respect to each V-UE's200 local clock and/or the angle-of-arrival (AoA) of the ranging signal.Since the one or more V-UEs 200 are likely moving, the V-UEs 200 areable to make several measurements of the P-UE's 300 ranging signals atdifferent positions. In contrast, since the P-UE 300 moves slowly, itsposition is assumed to be unchanged. This is illustrated in FIG. 5A.

In an aspect, the AoA can be measured using an array of antennas (e.g.,antenna(s) 202) that are close together (e.g., at the rooftop of theV-UE 200). If, however, different antennas are at different parts of theV-UE 200 (e.g., at the rooftop, near the side-mirrors, etc.), it can bemore challenging to estimate the AoA because the signal paths receivedby these antennas may be different. In fact, some of them may beNon-Line-of-Sight (NLOS). However, it is possible to identify whichantennas receive the Line-of-Sight (LOS) path by examining the channelprofile (including received power and channel impulse response) at eachantenna. For example, an LOS path typically has the highest receivedpower and has a dominant first peak in the channel impulse response.Thus, to better estimate the AoA, the channel profile at each antenna isexamined and, for each antenna, the received ranging signal is used tocalculate the AoA only if the channel profile of the ranging signal isdetermined to be LOS.

After measuring a series of ranging signals from the P-UE 300 at 404, at406, the one or more V-UEs 200 calculate an estimate of the position ofthe P-UE 300 and a confidence in that estimate based on the measurementsof the P-UE's 300 ranging signals and the V-UE(s)' 200 SPS position(s)at the times of the measurements. More specifically, a V-UE 200 willknow its own SPS position at the time it receives each ranging signalfrom the P-UE 300. Based on those known positions and the transmissiontimes and the AoAs of the received ranging signals, the V-UE 200 canestimate the position of the P-UE 300. For example, the V-UE 200 assumesthat the ranging signals travel at the speed of light, and therefore,can calculate the distance from the V-UE 200 to the P-UE 300 at each SPSposition at which it receives a ranging signal by multiplying the knowntransmission time of the ranging signal (the difference between thetimes the ranging signal was transmitted by the P-UE 300 and the timesthe ranging signal was received at the V-UE 200) by the known speed oflight. Combined with the AoA of the ranging signal and the known SPSposition of the V-UE 200, the V-UE 200 can calculate an estimate of theposition of the P-UE 300. The position may be represented as, forexample, x-y coordinates that are the distance and direction from thex-y coordinates (SPS position) of the V-UE 200. The V-UE 200 can thencombine (e.g., average) the position estimates calculated for each ofthe received ranging signals to generate a more accurate final positionestimate.

Note that the transmission time would be known in this case (excludingfor the clock errors at the transmitter and the receiver) as thetransmitter (e.g., P-UE 300) first informs the receiver (e.g., V-UE 200)of which resource (time and frequency) it will use to transmit theranging signal. Since a time-synchronous system can be assumed, the timeof the start of the resource is known. There are clock errors at thetransmitter and receiver, so the actual transmission time has some smallerror and so does the receiver's assumption of the subframe time. Theclock errors are cancelled later using round-trip-time (RTT)-likecalculations, as discussed below.

Further note that the SPS position of a V-UE 200 is generally moreaccurate than a P-UE's 300 SPS position since a V-UE 200 will generallyhave better GPS reception. Each of the one or more V-UEs 200 may alsoestimate the relative clock bias and clock drift between itself and theP-UE 300 by performing estimation over multiple measurements, under theassumption that the position of P-UE 300 remains largely unchangedduring the period of those measurements. Generally, the V-UE 200 will bemore confident about its estimation of the P-UE's 300 position if theangles of arrival of the series of ranging signals from the P-UE 300 areconsiderably different, as this allows for better triangulation.

More specifically, RTT procedures can be used to cancel the clock offsetbetween a transmitter (e.g., P-UE 300) and a receiver (e.g., a V-UE200). In an aspect, each node (e.g., V-UEs 200, P-UEs 300) broadcastranging signals, and other nodes respond with the measured ToAs of thoseranging signals within a small ranging time window (e.g., 4 ms). Thepurpose of the small ranging time window is to capture a snapshot of thelocal network and minimize clock drift. The distance between two nodescan be calculated as:

${\frac{c}{2}\left( {T_{2} - T_{1}} \right)} + {\frac{c}{2}\left( {T_{4} - T_{3}} \right)}$where T₁ is the transmission time of a ranging signal from thetransmitter, T₂ is the ToA of the ranging signal at the receiver, T₃ isthe transmission time of a response signal from the receiver, T₄ is theToA of the response signal at the transmitter, and c is the speed oflight. If the error in T₁ and T₄ are the same, then it cancels out. Ifthe error in T₂ and T₃ are the same, then it cancels out for the othernode as well.

The above RTT procedure can be performed periodically (e.g., everysecond) as a three-phase protocol. As a first phase, each node (e.g.,V-UEs 200, P-UEs 300) broadcasts the relative location of its antennasrelative to the center of the location of the node, identifiers of thesequences to be transmitted by those antennas, and the transmissionresources to be used. As a second phase, each node transmits a widebandsequence with the determined sequence identifier and resource (i.e., aranging signal). At a third phase, each node broadcasts the ToAs of theranging signals it received during the second phase and its own GPSlocation at the time of the second phase.

At 408, each V-UE 200 sends a message back to the P-UE 300 that containsthe V-UE's 200 estimated position of the P-UE 300 and the associatedconfidence in that position. To reduce the amount of time the P-UE 300is awake for the reception of the messages from the one or more V-UEs200, there may be a mapping between the resources on which the P-UE 300transmits the ranging signals and the resources on which it expects toreceive the response message(s) from the one or more V-UEs 200, asdiscussed above with respect to the three-phase protocol. Thus, the P-UE300 can be awake only for those time instants when it expects to receivethe response message(s). The P-UE 300 can also decide whether or not itwants to process all of the messages from different V-UEs 200. Forexample, to save power, the P-UE 300 can stop decoding further messagesonce it determines that it has a sufficient number of messages (positionestimates) from different V-UEs 200. In addition, to reduce the numberof message transmissions from different V-UEs 200 and to reducecollisions in the response resources, only those V-UEs 200 thatcalculated the position of the P-UE 300 above some confidence thresholdmay transmit a position message back to the P-UE 300 at 408. Thethreshold could be specified in the applicable standard, or may beencoded in the ranging signals from the P-UE 300 (e.g., the rangingsignal may include the threshold, or may include a value to a lookuptable of thresholds).

At 410, after receiving one or more such messages from the one or moreV-UEs 200, the P-UE 300 calculates a combined estimate of its position.The combined position estimate may consider the confidence of thereported position estimations. For example, the confidence in thecombined position estimate may be a combination of the confidence levelsin each of the constituent position estimates. In an aspect, the P-UE300 may combine the received estimates with its own position estimate(e.g., with its own SPS position), or adopt a position estimatecalculated by combining the position estimates received from the one ormore V-UEs 200 as its position. At 412, the P-UE 300 can then use thecombined estimation of its position and the associated confidence insubsequent BSMs that are optionally broadcast to neighboring UEs (e.g.,other P-UEs and/or V-UEs).

FIG. 6 illustrates an exemplary method 600 of the second mode for usingranging signals to determine an accurate position of a pedestrian (i.e.,a P-UE). In the first mode, the P-UE 300 estimates its position in orderto broadcast it in subsequent BSMs. In some cases, a P-UE 300 may be notcapable of BSM transmission or not interested in BSM transmission. Also,the P-UE 300 may intend to save power. In these situations, the P-UE 300can operate in the second mode, which is a simplified version of thefirst mode.

At 602, as at 402, the P-UE 300 transmits ranging signals in multipleranging resource pools. As discussed above, the P-UE 300 may transmitits ID along with the ranging signals. The P-UE 300 may also indicatethat it is in the second mode. In an aspect, the ID and the modeindication may be encoded in the ranging signal. For example, theranging signal may be a Zadoff-Chu sequence, and the sequence ID mayindicate the ID of the P-UE 300 and the use of the second mode.

At 604, one or more V-UEs 200 in communication range of the P-UE 300receive the ranging signals from the P-UE 300 and measure variousproperties of each ranging signal. As discussed above, these propertiesmay include the ToA of the ranging signal with respect to the V-UE's 200clock and/or the AoA of the ranging signal.

At 606, after measuring a series of ranging signals from the P-UE 300,each V-UE 200 can calculate an estimate of the position of the P-UE 300and a confidence in the estimate based on the measurements of thereceived ranging signals and the V-UE's 200 SPS positions at the timesof the measurements. Once a V-UE 200 has estimated the position of theP-UE 300, the V-UE 200 can avoid going near the P-UE 300 by, asnecessary, changing its path, reducing its speed, etc. At 608, the V-UE200 can optionally transmit a message (e.g., a BSM) containing thisinformation to other V-UEs 200 (e.g., a pedestrian has been detected atthis position and, optionally, with this confidence).

In contrast with the first mode, the one or more V-UEs 200 that receivedthe ranging signals from the P-UE 300 at 604 do not send a message backto the P-UE 300, based on the indication that the P-UE 300 is in thesecond mode. In this way, the second mode is quite power efficient forP-UEs 300, as the P-UEs 300 merely transmit ranging signals and thensleep; they do not receive anything in response as in the first mode.

FIG. 7 illustrates an exemplary method 700 of the third mode for usingranging signals to determine an accurate position of a pedestrian (i.e.,a P-UE). In the third mode, V-UEs 200 transmit ranging signals and P-UEs300 passively listen. Specifically, at 702, one or more V-UEs 200transmit ranging signals in one or more ranging resource pools. Asdescribed above, the ranging resource pool may consist of a set of timeand/or frequency resources (e.g., 10 subframes in LTE/5G terminology)and may occur periodically (e.g., once every second). The one or moreV-UEs 200 may transmit a ranging signal in each of several consecutiveranging resource pools.

In an aspect, each V-UE 200 may transmit its ID along with the rangingsignals. The ID may be encoded in, for example, the ranging signals. Forexample, the ranging signals may be Zadoff-Chu sequences, and thesequence ID may correspond to the ID of the V-UE 200. By assigningorthogonal Zadoff-Chu sequences to each V-UE 200, the cross-correlationof simultaneous transmissions from V-UEs 200 is reduced, therebyreducing interference and uniquely identifying V-UE 200 transmissions.

At 704, a P-UE 300 that intends to refine its position and is incommunication range of the one or more V-UEs 200 can measure one or moreproperties of each received ranging signal. These properties may includethe ToA of the ranging signal with respect to the P-UE's 300 local clockand/or the AoA of the ranging signal at the P-UE 300. Since the one ormore V-UEs 200 are moving, the P-UE 300 can make several measurements ofthe ranging signals from each of the one or more of the V-UEs 200 atdifferent positions of the one or more V-UEs 200. Since the P-UE 300moves slowly, its position can be assumed to be unchanged during thesemeasurements. This is illustrated in FIG. 5B.

After measuring a series of ranging signals from one or more V-UEs 200,at 706, the P-UE 300 can calculate an estimate of its own position andan associated confidence level based on the measurements of the rangingsignals and the SPS positions of the V-UEs 200 at the times of themeasurements. For example, the P-UE 300 can estimate its position basedon the SPS positions of a V-UE 200 when it transmits ranging signals andthe transmission times and the AoAs of the received ranging signals, asdiscussed above with reference to FIG. 4, but with the roles of the V-UE200 and the P-UE 300 reversed. The SPS positions of the one or moreV-UEs 200 may be derived from the BSMs broadcast by the V-UEs 200. In anaspect, the P-UE 300 may estimate its own position and the clock biasesand clock drifts between the P-UE 300 and the one or more V-UEs 200.

In an aspect, the P-UE 300 may measure one or more ranging signals fromdifferent V-UEs 200, but not enough ranging signals from any one V-UE200 to estimate the position of the P-UE 300 based on the rangingsignals from that V-UE 200 alone, or at least not enough to estimate theposition of the P-UE 300 within a threshold degree of accuracy. In thatcase, the P-UE 300 can calculate a single position estimate based on thecombined ranging signals from multiple V-UEs 200.

Alternatively, the P-UE 300 may be able to measure a sufficient numberof ranging signals from each of one or more V-UEs 200 to calculate aposition estimate based on the ranging signals from each V-UE 200. TheP-UE 300 may calculate a confidence level in each position estimatecalculated based on the measurements of each set of ranging signals froma V-UE 200. Generally, the confidence level associated with a positionestimate calculated based on a series of ranging signals from a givenV-UE 200 will be higher if the angles of arrival of the series ofranging signals are considerably different. The P-UE 300 can thencalculate a position estimate from the multiple position estimates byconsidering the associated confidence levels. For example, the P-UE 300may only use position estimates with an associated confidence level thatis above some threshold. The P-UE 300 can then combine the positionestimates that have a confidence level above that threshold.

In an aspect, to reduce the power consumption of the P-UE 300, the P-UE300 can determine a threshold accuracy level. Once the P-UE 300 hasmeasured a sufficient number of ranging signals to calculate a positionestimate having at least that threshold accuracy, it can stop measuringranging signals.

At 708, the P-UE 300 can then use the calculated estimate of itsposition in subsequent BSMs that are optionally broadcasted toneighboring UEs (e.g., other P-UEs and/or V-UEs), or for otherlocation-based services (e.g., navigation).

The different modes of operation described above with reference to FIGS.4, 6, and 7 may coexist within the same system, provided both P-UEs andV-UEs can transmit ranging signals. The different modes may bedifferentiated by the ranging signals. For example, there may be atleast three sets of sequence IDs associated with ranging signals, onefor each mode. Within each set of ranging signals, a sequence ID can bemapped to a UE ID. Based on the sequence ID of a received rangingsignal, the receiving UE (whether a P-UE 300 or a V-UE 200) can operateaccording to the identified mode. As will be appreciated, however, thedifferentiation of different modes may be achieved in other ways. Forexample, modes can be differentiated by using a combination of sequenceID and an explicit indication of the mode.

In some cases, one mode may provide better performance than another. Forexample, since a V-UE 200 may be able to determine better AoAmeasurements (e.g., due to a larger antenna array and the spatialseparation of the antenna elements) than a P-UE 300, the first two modesmay provide better estimation of the P-UE's 300 position. Therefore, aP-UE 300 may switch between different modes based on its assessment ofthe current accuracy of its position and/or other factors.

For example, if a P-UE 300 assesses that its current position accuracyis poor (based on, for example, poor SPS reception in a recent timewindow), it may initiate operation of the first mode by starting totransmit ranging signals. Alternatively, if a P-UE 300 has assessed thatits current position accuracy is sufficiently good, it can use the thirdmode by passively listening to the ranging signals from V-UEs 200. Inyet another alternative, if a P-UE 300 is not capable of or interestedin BSM transmission, or intends to conserve power, it may choose thesecond mode.

FIG. 8 illustrates an exemplary method 800 for using ranging signals todetermine a position of a pedestrian (e.g., P-UE 300) according to atleast one aspect of the disclosure. The method 800 may be performed by afirst UE operating in any of the three modes described above withreference to FIGS. 4, 6, and 7. As shown below, the method 800 may beperformed by a V-UE 200 or a P-UE 300. At 802, the first UE (e.g.,transceiver 204, WAN transceiver 304, or WLAN transceiver 306) receivesa plurality of ranging signals transmitted by one or more other UEs(e.g., one or more V-UEs 200 or a P-UE 300), as described above withreference to 404 of FIG. 4, 604 of FIG. 6, and 704 of FIG. 7. At 804,the first UE (e.g., transceiver 204 and/or processor 210, or WANtransceiver 304 or WLAN transceiver 306 and/or processor 310) measuresone or more properties (e.g., ToA, AoA) of each of the plurality ofranging signals, as described above with reference to 404 of FIG. 4, 604of FIG. 6, 704 of FIG. 7. At 806, the first UE (e.g., processor 210 orprocessor 310) calculates an estimate of the position of the P-UE basedon the one or more properties of each of the plurality of rangingsignals, as described above with reference to 406 of FIG. 4, 606 of FIG.6, 706 of FIG. 7. By performing operations 802 to 806, the first UE isable to determine an accurate position of the P-UE, which is beneficialwhere an accurate position of the P-UE is not otherwise available (e.g.,where the P-UE does not have an accurate SPS position yet, or is notbroadcasting its position to other UEs).

At 808, the first UE (e.g., processor 210 or processor 310) optionallycalculates a confidence level in the estimate of the position of theP-UE, as described above with reference to 406 of FIG. 4, 606 of FIG. 6,706 of FIG. 7. Operation 808 is optional because a confidence level doesnot need to be calculated. However, a benefit of calculating theconfidence is that the first UE, or a different UE receiving theposition estimate, will have an indication of how accurate the positionestimate is, and therefore, to what extent it can rely on the positionestimate.

At 810, the first UE (e.g., transceiver 204, WAN transceiver 304, orWLAN transceiver 306) optionally transmits (e.g., in a BSM) the estimateof the position of the P-UE to a second UE (e.g., one or more V-UEs 200or the P-UE 300), and optionally the associated confidence level, asdescribed above with reference to 408 of FIG. 4, 608 of FIG. 6, 708 ofFIG. 7. Operation 810 is optional because the first UE need not transmitthe position estimate, it can simply use it for its own purposes.However, a benefit of transmitting the position estimate, and optionallythe confidence level, is that other nearby UEs will be able to use theposition estimate of the P-UE in their own decision making (e.g., coursechanges, speed changes, etc.) or in combination with their own estimatesof the position of the P-UE.

In an aspect, as described above, the confidence level may be based onAoAs of the plurality of ranging signals. As described above, the largerthe differences between the AoAs of the plurality of ranging signals,the higher the confidence level, as larger differences between the AoAsallows for better triangulation.

In an aspect, the calculation of the position of the P-UE assumes thatthe P-UE is stationary. Although the P-UE may not be stationary, this isa reasonable assumption, as the P-UE is likely moving very slowly (e.g.,at the pace of a walking pedestrian) compared to the speed of a V-UE,and simplifies the calculation of the position estimate.

In an aspect, the plurality of ranging signals may comprise a pluralityof Zadoff-Chu sequences, and the sequence IDs of the plurality ofranging signals may correspond to the ID of the first UE. By assigningorthogonal Zadoff-Chu sequences to each P-UE and/or V-UE, thecross-correlation of simultaneous transmissions from P-UEs and V-UEs isreduced, thereby reducing interference and uniquely identifying P-UE andV-UE transmissions.

In an aspect, the plurality of ranging signals may be transmittedperiodically in consecutive resource pools. A benefit of using specifiedresource pools is that other UEs will know where and how to receive theplurality of ranging signals, and interference can be mitigated.

In an aspect, if the one or more UEs comprise a plurality of V-UEs, thefirst UE can calculate a plurality of estimates of the position of theP-UE based on properties (e.g., ToA, AoA) of each of the plurality ofranging signals. In this aspect, calculating the estimate of theposition of the P-UE at 806 may include calculating the estimate of theposition of the P-UE by combining the plurality of estimates of theposition of the P-UE. A combined position estimate may have a higherconfidence level than a single position estimate, as it is based on moremeasurements than a single position estimate.

FIG. 9 illustrates an exemplary method 900 for determining a position ofa P-UE (e.g., P-UE 300) according to at least one aspect of thedisclosure. The method 900 may be performed by the P-UE (e.g., P-UE 300)operating in the first mode described above with reference to FIG. 4. At902, the P-UE 300 (e.g., WAN transceiver 304 or WLAN transceiver 306)transmits a plurality of ranging signals in a plurality of rangingresource sets, as described above with reference to, for example, 402 ofFIG. 4. At 904, the P-UE 300 (e.g., WAN transceiver 304 or WLANtransceiver 306) receives a first message (e.g., a BSM) from a firstV-UE (e.g., a V-UE 200), the first message including a first estimatedposition of the P-UE and a first indicator of confidence of the firstestimated position, as described above with reference to, for example,408 of FIG. 4. At 906, the P-UE 300 (e.g., WAN transceiver 304 or WLANtransceiver 306) receives a second message (e.g., a BSM) from a secondV-UE (e.g., a V-UE 200), the second message including a second estimatedposition of the P-UE and a second indicator of confidence of the secondestimated position, as described above with reference to, for example,408 of FIG. 4. At 908, the P-UE 300 (e.g., processor 310) calculates anestimate of the position of the P-UE 300 based on the first estimatedposition, the first indicator, the second estimated position, the secondindicator, or a combination thereof, as described above with referenceto, for example, 410 of FIG. 4.

At 910, the P-UE 300 (e.g., WAN transceiver 304 or WLAN transceiver 306)optionally transmits a message (e.g., a BSM) including the estimate ofthe position of the P-UE 300. Operation 910 is optional because the P-UE300 need not transmit its position estimate, but rather, can use it onlyfor its own purposes (e.g., refining its SPS position, providing it toan application providing position-based services (e.g., mapping), etc.).

In an aspect, the P-UE 300 may adopt the first estimated position or thesecond estimated position based on which of the first indicator or thesecond indicator indicates a higher confidence level. This is beneficialbecause it reduces the complexity of the calculations that the P-UEneeds to perform. That is, the P-UE need not combine any positionestimates, but rather, simply adopts one of them.

In an aspect, the calculating at 908 includes setting, by the P-UE, theestimate of the position of the P-UE as an average of the firstestimated position and the second estimated position. A benefit of usingthe average of the position estimates is that if neither confidenceindicator is significantly higher than the other, the average of theposition estimates may provide a more accurate position of the P-UE 300.

In an aspect, as described above, the confidence level may be based onAoAs of the plurality of ranging signals. As described above, the largerthe differences between the AoAs of the plurality of ranging signals,the higher the confidence level, as larger differences between the AoAsallows for better triangulation.

In an aspect, the calculation of the position of the P-UE assumes thatthe P-UE is stationary. Although the P-UE may not be stationary, this isa reasonable assumption, as the P-UE is likely moving very slowly (e.g.,at the pace of a walking pedestrian) compared to the speed of a V-UE,and simplifies the calculation of the position estimate.

In an aspect, the plurality of ranging signals may comprise a pluralityof Zadoff-Chu sequences, and the sequence IDs of the plurality ofranging signals may correspond to the ID of the first UE. By assigningorthogonal Zadoff-Chu sequences to each P-UE and/or V-UE, thecross-correlation of simultaneous transmissions from P-UEs and V-UEs isreduced, thereby reducing interference and uniquely identifying P-UE andV-UE transmissions.

In an aspect, the plurality of ranging signals may be transmittedperiodically in consecutive resource pools. A benefit of using specifiedresource pools is that other UEs will know where and how to receive theplurality of ranging signals, and interference can be mitigated.

FIG. 10 illustrates an example apparatus 1000 represented as a series ofinterrelated functional modules. In an aspect, the apparatus 1000 maycorrespond to the V-UE 200 or the P-UE 300. A module for receiving 1002may correspond at least in some aspects to, for example, a communicationdevice, such as transceiver 204 in FIG. 2 or WAN transceiver 304 or WLANtransceiver 306 in FIG. 3, as discussed herein. A module for measuring1004 may correspond at least in some aspects to, for example, acommunication device in conjunction with a processing system, such astransceiver 204 in FIG. 2 or WAN transceiver 304 or WLAN transceiver 306in FIG. 3 in conjunction with processor 210 in FIG. 2 or processor 310in FIG. 3, respectively, as discussed herein. A module for calculating1006 may correspond at least in some aspects to, for example, aprocessing system, such as processor 210 in FIG. 2 or processor 310 inFIG. 3, as discussed herein. An optional module for calculating 1008 maycorrespond at least in some aspects to, for example, a processingsystem, such as processor 210 in FIG. 2 or processor 310 in FIG. 3, asdiscussed herein. An optional module for transmitting 1010 maycorrespond at least in some aspects to, for example, a communicationdevice, such as transceiver 204 in FIG. 2 or WAN transceiver 304 or WLANtransceiver 306 in FIG. 3, as discussed herein.

FIG. 11 illustrates an example P-UE apparatus 1100 represented as aseries of interrelated functional modules. In an aspect, the apparatus1100 may correspond to the P-UE 300. A module for transmitting 1102 maycorrespond at least in some aspects to, for example, a communicationdevice, such as WAN transceiver 304 or WLAN transceiver 306 in FIG. 3,as discussed herein. A module for receiving 1104 may correspond at leastin some aspects to, for example, a communication device, such as WANtransceiver 304 or WLAN transceiver 306 in FIG. 3, as discussed herein.A module for receiving 1106 may correspond at least in some aspects to,for example, a communication device, such as WAN transceiver 304 or WLANtransceiver 306 in FIG. 3, as discussed herein. A module for calculating1108 may correspond at least in some aspects to, for example, aprocessing system, such as processor 310 in FIG. 3, as discussed herein.An optional module for transmitting 1110 may correspond at least in someaspects to, for example, a communication device, such as WAN transceiver304 or WLAN transceiver 306 in FIG. 3, as discussed herein.

The functionality of the modules of FIGS. 10-11 may be implemented invarious ways consistent with the teachings herein. In some designs, thefunctionality of these modules may be implemented as one or moreelectrical components. In some designs, the functionality of theseblocks may be implemented as a processing system including one or moreprocessor components. In some designs, the functionality of thesemodules may be implemented using, for example, at least a portion of oneor more integrated circuits (e.g., an ASIC). As discussed herein, anintegrated circuit may include a processor, software, other relatedcomponents, or some combination thereof. Thus, the functionality ofdifferent modules may be implemented, for example, as different subsetsof an integrated circuit, as different subsets of a set of softwaremodules, or a combination thereof. Also, it will be appreciated that agiven subset (e.g., of an integrated circuit and/or of a set of softwaremodules) may provide at least a portion of the functionality for morethan one module.

In addition, the components and functions represented by FIGS. 10-11, aswell as other components and functions described herein, may beimplemented using any suitable means. Such means also may beimplemented, at least in part, using corresponding structure as taughtherein. For example, the components described above in conjunction withthe “module for” components of FIGS. 10-11 also may correspond tosimilarly designated “means for” functionality. Thus, in some aspectsone or more of such means may be implemented using one or more ofprocessor components, integrated circuits, or other suitable structureas taught herein.

It should be understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations may be used herein as a convenient method of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements may be employed there or that the first element must precedethe second element in some manner. Also, unless stated otherwise a setof elements may comprise one or more elements. In addition, terminologyof the form “at least one of A, B, or C” or “one or more of A, B, or C”or “at least one of the group consisting of A, B, and C” used in thedescription or the claims means “A or B or C or any combination of theseelements.” For example, this terminology may include A, or B, or C, or Aand B, or A and C, or A and B and C, or 2A, or 2B, or 2C, and so on.

In view of the descriptions and explanations above, one skilled in theart will appreciate that the various illustrative logical blocks,modules, circuits, and algorithm steps described in connection with theaspects disclosed herein may be implemented as electronic hardware,computer software, or combinations of both. To clearly illustrate thisinterchangeability of hardware and software, various illustrativecomponents, blocks, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

Accordingly, it will be appreciated, for example, that an apparatus orany component of an apparatus may be configured to (or made operable toor adapted to) provide functionality as taught herein. This may beachieved, for example: by manufacturing (e.g., fabricating) theapparatus or component so that it will provide the functionality; byprogramming the apparatus or component so that it will provide thefunctionality; or through the use of some other suitable implementationtechnique. As one example, an integrated circuit may be fabricated toprovide the requisite functionality. As another example, an integratedcircuit may be fabricated to support the requisite functionality andthen configured (e.g., via programming) to provide the requisitefunctionality. As yet another example, a processor circuit may executecode to provide the requisite functionality.

Moreover, the methods, sequences, and/or algorithms described inconnection with the aspects disclosed herein may be embodied directly inhardware, in a software module executed by a processor, or in acombination of the two. A software module may reside in Random-AccessMemory (RAM), flash memory, Read-only Memory (ROM), ErasableProgrammable Read-only Memory (EPROM), Electrically ErasableProgrammable Read-only Memory (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art, transitory or non-transitory. An exemplary storage medium iscoupled to the processor such that the processor can read informationfrom, and write information to, the storage medium. In the alternative,the storage medium may be integral to the processor (e.g., cachememory).

Accordingly, it will also be appreciated, for example, that certainaspects of the disclosure can include a transitory or non-transitorycomputer-readable medium embodying a method for transmitting vehicleinformation messages among a plurality of vehicles.

While the foregoing disclosure shows various illustrative aspects, itshould be noted that various changes and modifications may be made tothe illustrated examples without departing from the scope defined by theappended claims. The present disclosure is not intended to be limited tothe specifically illustrated examples alone. For example, unlessotherwise noted, the functions, steps, and/or actions of the methodclaims in accordance with the aspects of the disclosure described hereinneed not be performed in any particular order. Furthermore, althoughcertain aspects may be described or claimed in the singular, the pluralis contemplated unless limitation to the singular is explicitly stated.

What is claimed is:
 1. A method for using ranging signals to determine a position of a pedestrian user equipment (P-UE), comprising: receiving, at a first user equipment (UE), a plurality of ranging signals transmitted by at least one moving vehicular UE (V-UE) from a plurality of positions; measuring, by the first UE, one or more properties of each of the plurality of ranging signals; and calculating, by the first UE, an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals.
 2. The method of claim 1, wherein the one or more properties of each of the plurality of ranging signals comprise a time of arrival (ToA) of each of the plurality of ranging signals, an angle-of-arrival (AoA) of each of the plurality of ranging signals, or any combination thereof.
 3. The method of claim 2, wherein the ToA of each of the plurality of ranging signals is based on a local clock time of the first UE.
 4. The method of claim 1, further comprising: transmitting, by the first UE, the estimate of the position of the P-UE to a second UE.
 5. The method of claim 4, further comprising: calculating, by the first UE, a confidence level in the estimate of the position of the P-UE.
 6. The method of claim 5, wherein the confidence level is based on AoAs of the plurality of ranging signals, wherein the confidence level is higher based on larger differences between AoAs of the plurality of ranging signals.
 7. The method of claim 5, wherein transmitting the estimate of the position of the P-UE to the second UE further comprises transmitting, by the first UE, the confidence level in the estimate of the position of the P-UE to the second UE.
 8. The method of claim 4, wherein the first UE comprises a vehicle UE (V-UE) and the second UE comprises the P-UE.
 9. The method of claim 8, wherein the calculation of the estimate of the position of the P-UE is further based on a known position of the first UE.
 10. The method of claim 4, wherein the first UE comprises a first vehicle UE (V-UE) and the second UE comprises a second V-UE.
 11. The method of claim 10, wherein the first V-UE transmits the estimate of the position of the P-UE to the second V-UE in a Basic Safety Message.
 12. The method of claim 4, wherein the first UE comprises the P-UE and the second UE comprises a V-UE.
 13. The method of claim 1, wherein each of the plurality of ranging signals comprises a Zadoff-Chu sequence.
 14. The method of claim 1, wherein each of the plurality of ranging signals encodes an identifier of a UE by which the ranging signal was transmitted.
 15. The method of claim 1, wherein the plurality of ranging signals is transmitted periodically in consecutive resource pools.
 16. The method of claim 1, wherein a position of the P-UE is considered to be constant when calculating the estimate of the position of the P-UE.
 17. The method of claim 1, wherein the at least one V-UE comprises a single V-UE.
 18. The method of claim 1, wherein the at least one V-UE comprises a plurality of V-UEs.
 19. The method of claim 18, wherein the first UE calculates a plurality of estimates of the position of the P-UE based on properties of each of the plurality of ranging signals received from the plurality of V-UEs, and wherein calculating the estimate of the position of the P-UE comprises calculating the estimate of the position of the P-UE by combining the plurality of estimates of the position of the P-UE.
 20. A method for determining a position of a pedestrian user equipment (P-UE), comprising: transmitting, by the P-UE, a plurality of ranging signals in a plurality of ranging resource sets; receiving, at the P-UE, a first message from a first vehicle user equipment (V-UE), the first message including a first estimated position of the P-UE and a first indicator of confidence of the first estimated position; receiving, at the P-UE, a second message from a second V-UE, the second message including a second estimated position of the P-UE and a second indicator of confidence of the second estimated position; and calculating, by the P-UE, an estimate of the position of the P-UE based on the first estimated position, the first indicator, the second estimated position, the second indicator, or a combination thereof.
 21. The method of claim 20, further comprising transmitting a basic safety message (BSM) including the estimate of the position of the P-UE.
 22. The method of claim 20, wherein the plurality of ranging signals includes at least a first set of ranging signals transmitted using a first set of transmission resources for the P-UE and a second set of ranging signals transmitted using a second set of transmission resources for the P-UE.
 23. The method of claim 20, further comprising transmitting an identifier of the P-UE, a mode of the P-UE, or both.
 24. The method of claim 23, wherein each of the plurality of ranging signals comprises a Zadoff-Chu sequence having a sequence identifier, and wherein the sequence identifier is the identifier of the P-UE.
 25. The method of claim 24, wherein the Zadoff-Chu sequence includes an indication of the mode of the P-UE.
 26. The method of claim 20, wherein the calculating comprises: adopting, by the P-UE, the first estimated position or the second estimated position based on which of the first indicator or the second indicator indicates a higher confidence level.
 27. The method of claim 20, wherein the calculating comprises: setting, by the P-UE, the estimate of the position of the P-UE as an average of the first estimated position and the second estimated position.
 28. The method of claim 20, wherein a position of the P-UE is considered to be constant when calculating the estimate of the position of the P-UE.
 29. An apparatus for using ranging signals to determine a position of a pedestrian user equipment (P-UE), comprising: a transceiver of a first user equipment (UE) configured to: receive a plurality of ranging signals transmitted by at least one moving vehicular UE (V-UE) from a plurality of positions; and measure one or more properties of each of the plurality of ranging signals; and at least one processor of the first UE configured to calculate an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals.
 30. An apparatus for determining a position of a pedestrian user equipment (P-UE), comprising: a transceiver of the P-UE configured to: transmit a plurality of ranging signals in a plurality of ranging resource sets; receive a first message from a first vehicle user equipment (V-UE), the first message including a first estimated position of the P-UE and a first indicator of confidence of the first estimated position; and receive a second message from a second V-UE, the second message including a second estimated position of the P-UE and a second indicator of confidence of the second estimated position; and at least one processor of the P-UE configured to calculate an estimate of the position of the P-UE based on the first estimated position, the first indicator, the second estimated position, the second indicator, or a combination thereof. 